Continuous tension tower

ABSTRACT

A CONTINUOUS TENSION TOWER IS SHOWN WHEREIN A TENSION APPLYING MEMBER, SUCH AS A CHAIN, IS ROUTED, OVER TWO OR MORE SHEAVES MOUNTED ON A TOWER, BETWEEN A WORKPIECE AND A LEVER. A TENSION FORCE IS APPLIED TO THE CHAIN BY A LIMITED STROKE FORCE APPLYING EXPANSIBLE FLUID MOTOR WHICH ACTS ON THE LEVER. THE LEVER IS ADAPTED TO PROVIDE A VARIABLE LEVER ARM RATIO BETWEEN THE MOTOR AND THE CHAIN. A TENSION RETAINING MEMBER IS ALSO LOCATED ON THE TOWER TO MAINTAIN THE TENSION ON THE CHAIN WHEN THE FORCE ON THE MOTOR IS RELEASED.

March 2, 1971 H. J. BERENDT ET 1. 3,566,666

I CONTINUOUS TENSION TOWER Filed Aug, 20, 1968 2 Sheets-Sheet! IN VEN'I'URS Mai-ch 2, 1971 H. J. BERENDT ETAL 3,566,666

CONTINUOUS TENSION TOWER Filed Aug. 20. 1968 2 Sheets-Sheet 2 #012151 j/gnezzagfi 05: 113 fiamsgy United States Patent 3,566,666 CONTINUOUS TENSION TOWER Harry J. Berendt, 9251 Rocklaud, Detroit, Mich. 48239, and Robert R. Ramsay, 18101 Magnolia Parkway, Southfield, Mich. 48075 Filed Aug. 20, 1968, Ser. No. 753,950 Int. Cl. B21d 11/00; B21 7/46, 13/00 U.S. Cl. 72-444 3 Claims ABSTRACT OF THE DISCLOSURE A variety of frame straightening devices are available which use an expansible fluid motor. When the expansible fluid motor is used only a limited stroke is available. Therefore, when the motor is extended to full stroke, but the workpiece has not been fully straightened, the motor must be restroked. To restroke the motor, the chain which transmits the force from the motor to the workpiece, must be repositioned. Generally as the tension on the chain is released the workpiece will return toward its original configuration. To prevent any loss of energy which has been transmitted to the workpiece, the present invention uses a tension retaining device to maintain the tension on the chain when the motor force is released, Thus, the entire energy transmitted to the workpiece is conserved therein. Also, many workpieces will require a force that is greater than the motor is capable of delivering. To provide for this situation, the present invention has a variable ratio lever arm.

It is, therefore, an object of this invention to provide in an improved tension tower, having a limited stroke motor and a tension applying member, tension retaining means for maintaining the tension on the tension applying member when the motor is restroked.

It is another object of this invention to provide in an improved tension tower a lever having a variable lever ratio and means for maintaining the tension force applied by the lever.

It is still another object of this invention to provide in an improved tension tower a force applying lever, a limited stroke fluid motor for applying a force to a chain through the lever and a pin operatively connecting the chain to the tower to maintain the force on the chain when the motor is restroked.

Other objects and advantages will become apparent from the following description and drawings in which:

FIG. 1 is an elevation view of a beam type frame straightening machine;

'FIG. 2 is an enlarged view partly in section of the continuous tension tower;

FIG. 3 is a side view of the tower shown in FIG. 2;

FIG. 4 is a modification of the tower in FIG. 2 adapted for use on a box type frame machine;

3,566,666 Patented Mar. 2, 1971 ice FIG. 5 is a plan view of the lever;

FIG. 6 is an elevation view of a modification of the tension retaining device;

FIG 7 is another modification of the tension retaining device.

Referring to the drawings, where corresponding designations represent like or corresponding parts, and particularly FIGS. 1, 2 and 3, there is shown a tower 10 having two parallel sides 12 and 14 which are spaced and secured together by a plurality of straps 16 welded to the sides. Also secured to the tower is an upper mounting bracket 18 which has an angle member 20 adapted to receive one end 21 of an expansible fluid motor 22. A moveable mounting member 24 is pivotally mounted by a fastener 26 on a extension 28 welded to the lower end of the tower 10. The moveable member 24 includes a lever 30, rotatably mounted on the fastener 26, and a pin 32. in openings 34 in the lever 30. The other end 35 of the fluid motor 22 is connected to the lever 30 such that when the fluid motor 22 is operated the lever 30 will pivot about the fastener 26 relative to the tower 10. The lever 30 has a plurality of attachment openings or key slots 36 adapted to receive a tension force trans mitting member such as a chain 38 or a multistrand wire rope. A tension spring 40 is connected between a pin 42 on the tower and a pin 44 on the lever 30 to maintain the lever 30 in the position shown, thus urging the fluid motor 22 to the unexpanded position. The fluid motor 22 is preferably of the conventional hydraulic piston and cylinder type, which may be operated by a conventional manual hydraulic pump or an air over hydraulic pump, which is available in most auto repair shops, attached to the hose 46.

A lower sheave or pulley 48 is rotatably mounted on a pin 50 which is located in a pair of a plurality of openings 52 in the sides 12 and 14. The sheave 48 may be moved higher or lower on the tower 10 by changing the location of the pin 50. This provides a plurality of locations from which the chain 38 may be directed from the tower to a workpiece. An upper sheave or pulley 54- is also rotatably mounted on the tower 10 by a pin 56 which is located in a pair of openings 58. The sheaves 48 and 54 are adapted to route the chain 38 from the lever 30 to a workpiece, such as a damaged automobile body panel or frame, A hook 59, or other attachment device, is used to connect the chain 38 to the workpiece. Thus when the expansible fluid motor 22 is operated, the force and movement, applied thereby to the lever, will be transmitted via the chain 38 to the workpiece.

In many instances a single stroke of the motor 22 is not suflicient to return the workpiece to its original configuration. Therefore it is necessary to return the motor 22 to the unexpected position shown and adjust the chain 38 on the lever 30 to permit another stroke of the motor 22 to the unexpanded position shown and adjust the chain configuration of the workpiece is obtained. However, when the force on the motor .22 is released, the chain 38, lever 30 and motor 22 will be drawn backward due to the energy stored in the workpiece. In fact, if the yield point of the material of the workpiece, such as a steel frame, is sufliciently high, the entire movement of the motor 22 may be lost and no change in the configuration of the workpiece will occur. Therefore, a tension retaining device, such as a pin 60 is inserted in a link of the chain 38 abutting the lower side of the mounting bracket 18,

when the motor 22 has been fully extended. Thus, when the force on the motor 22 is released, the tension on the chain 38 is maintained between the bracket 18 and the workpiece. The lower end of the chain, however, is free to be relocated on the lever 30, so that another pull may be made on the workpiece with a minimum amount of lost motion or energy.

The extension 28 has two horizontally extending bars 62 and 64- which are welded to the sides 12 and 14. Extending upward from between the bars 62 and 64 and welded thereto is a bracket 66 to which the lever 30 is pivotally connected. Depending downwardly from between the bars 62 and 64 and welded thereto is an attachment leg 68. The attachment leg 68 has two openings 70 and 72 through which fasteners 74 and 76 are placed to secure the tower 10 to a horizontal beam or rail 78. Thus producing a device commonly termed a beam or rail type frame straightening machine which is commonly found in auto repair shops.

The tower 10 is also readily adaptable to a fixed platform type frame straightening machine. By selectively placing two or more of the towers 10 on a fixed platform machine, a wide variety of pulling operations can be performed simultaneously. The tower 10, when used with a fixed platform machine, is adapted to be moveable from one location to another on the machine thus further increasing the versatility of the machine. With a slight modification, such as that shown in FIG. 4, the tower 10 may also be used with a box type frame straightening machine. Generally in a box type machine two pairs of trolley tracks 80 and 8 2 are horizontally spaced from each other. A second attachment leg 68 is welded or otherwise secured to the upper end of the tower 10. A trolley 84 is then adjustably connected to each of the attachment legs 68 and 68' so that the tower 10 is located between the rails 80 and 82. The rails 80 and 82 are continuous and form a rectangular box such that, when a workpiece is placed within the box, the towers 10 may be positioned anywhere about the perimeter of the tower. Thus a continuous tension force may be applied to the workpiece at any point thereon and essentially from any angle.

To increase the tension force available with an expansible fluid motor of a given size the lever 30, shown in FIG. 5, has a plurality of key slots 36 formed therein. Thus, the chain 38 may be moved relative to the pivot axis 86. As the chain 38 is moved toward the pivot axis 86, the force of the motor 22 is multiplied by the ratio of the lever arms between the motor 22 and the chain attachment point in one of the key slots 36. When the chain 38 is relocated on the lever 30', the tension spring 40 may be located between the pin 42 and the pin 44, or any of the key slots 36; or between an opening 88 and the angle member 20.

The tower 10 may also be used with a snatch block to multiply the pulling force of the motor 22, as is common practice in auto body repair. When a snatch block is used, the chain 38 is routed around a pulley on the snatch block; and the hook is connected to the tower '10 with a pin placed in one of the pairs of openings -2. A second chain is connected between the center of the snatch block pulley and the workpiece. Thus a two to one multiplier is provided. When a snatch block is used in combination with adjustable lever arm ratio of the lever 30, a wide variety of tension multipliers are obtained.

While the preferred method of retaining the tension on the tension force applying member is described above, many other methods and apparatus are possible. As seen in FIG. 6 the upper pulley 54 is provided with a plurality of radially extending fingers 90 which are spaced about the periphery thereof. The spacing of the fingers 90 is determined by the link spacing of the chain 38 such that every other link is engaged by one of the fingers 90. A plurality of axial openings 92 are formed in the side faces of the pulley 54'. As the pulley 54 is rotated,

when tension is applied to the workpiece, the openings 92 rotates past a plurality of pairs of openings 94 in the tower sides 12 and 14. When the motor 22 has reached the full stroke position, at least one of the openings 92 Will be aligned with one of the pairs of openings 94. A pin is inserted in the aligned openings, thus holding the pulley 54 and the chain 38 stationary when the fluid pressure on the motor 22 is released, thereby retaining the tension on the chain 38.

If a multistrand wire rope 96 is used, a tension retaining device 98, shown in FIG. 7, may be used. The retaining device 98 includes a restraining bracket 100 which is mounted on the upper mounting bracket 18 or in any convenient location on the tower 10. The restraining bracket 100 has a frusto-conical seat 102 into which is fitted a split or two piece frusto-conical lock 104 which has a saw-toothed cylindrical opening 106 therethrough. The wire rope 96 is passed through the opening 106 and detachably connected to the lever 30. The connection between the Wire rope 96 and the lever 30 may be provided by a device similar to the retaining device 98 or keyslots. As the motor 22 is extended, the wire rope 96 passes through the opening 106, in the direction of arrow A, and the frusto-conical surface of the lock does not contact the frusto-conical surface of the seat 102. However, as the pressure in the motor 22 is released and the wire rope begins to retract to relieve the tension force, the frusto-conical surfaces of the lock 104 and the seat 102 contact each other, thereby causing the lock 104 to close on the wire rope 96. Thus, the tension on the wire rope is retained while the wire rope 96 is repositioned on the lever 30.

It should be understood that the exact details of construction shown and described are not intended as limitations, for obvious modifications will occur to a person skilled in the art.

What is claimed is:

1. A continuous tension tower for applying tension force to a workpiece comprising in combination tower means including a tower, a first pulley rotatably mounted in a fixed position adjacent the upper end of said tower, a second rotatable pulley selectively mountable in a plu rality of positions adjacent one side of said tower, and attachment means for securing the tower in a stationary position; force applying means including a bracket mounted on said tower, lever means pivotally mounted on said tower and fluid force motor means mounted between the bracket and the lever means for applying a force to the lever means; force transmitting means for transmitting the force of said fluid force motor means to the workpiece being detachably connected to said lever means and the workpiece and routed substantially degrees around said first and substantially 90 degrees around said second pulley between said lever means and the workpiece; fluid source means for operating said fluid force motor means; and force retaining means for selectively operatively connecting said force transmitting means and said tower means for retaining the force on said force transmitting means when the force of the fluid force motor means is released whereby said force transmitting means may be detached from said lever means.

2. The invention defined in claim 1 and said lever means including mounting means for said fluid force motor means, a pivot axis common to said lever means and said tower means and attachment means for attaching said force transmitting means at a plurality of lever ratios on said lever means.

3. A continuous tension tower for applying tension force to a workpiece comprising in combination tower means including a tower and first and second pulleys rotatably mounted on said tower at a fixed position adjacent the upper end of said tower and at a plurality of selective positions adjacent one side of said tower respectively; force applying means including motor mounting means comprising a fixed member secured to said tower means and a moveable member operatively connected to said tower means and expansible fluid motor means mounted between said fixed and moveable members and adapted to transmit a force to said moveable member; force transmitting means for transmitting the force of said expansible fluid motor means from said moveable member to the workpiece and being directed substantially 90 degrees around said second pulley and 180 degrees around said first pulley between the workpiece and said moveable member and being detachably connected to said moveable member; and force retaining means for operatively connecting said force transmitting means and said tower means for retaining the force on said force transmitting means when said force transmitting means is detached from said moveable member.

References Cited UNITED STATES PATENTS 4/1961 Ferguson 72-705 8/1967 Eck 72-705 US. Cl. X.R. 

